In certain chip bonding applications, a semiconductor device may need to be heated to a predetermined temperature in order to create conditions for bonding. For example, interconnects of a semiconductor device may have to be heated to their melting points to enable bonding of the semiconductor device to a substrate via such interconnects. In particular, bond heads incorporating pulse heating elements are popularly used in flip chip applications. Such pulse heating elements are capable of rapidly heating the bond head and thus the semiconductor device to reduce bonding cycle time. Thereafter, the semiconductor device should be cooled to hasten solidification of the interconnects to fix the semiconductor device onto the substrate.
Patent publication number WO 2013/101212 entitled “Direct Air Impingement Cooling of Package Structures” discloses a heater for heating a bond head which is cooled by direct air impingement. Various embodiments of microelectronics packing cooling assemblies are described, including a cooling assembly comprising an array of vertically separated micro channels coupled to a heat spreader, wherein the heat spreader is finless and each inlet micro channel has two adjacent outlet micro channels.
Generally, after heating of a bond head is performed by a heater plate, the air flow streaming through flow channels in an insulation block is used to cool the heater plate. The flow channels usually include some small holes in the insulation block. The insulation block is made from material that has low thermal conductivity and low coefficient of thermal expansion. The aim is to generate a high flow speed and thus a high cooling rate for the heater plate.
However, the designer typically has to place priority on material properties of the insulation block, such as having a low thermal conductivity and coefficient of thermal expansion, and may need to compromise heating capacity and fabrication freedom due to the limited choice of fabrication material. Accordingly, the flow speed and flow pattern are limited during the mechanical fabrication of the insulation block. As a result, it is difficult to further optimize the cooling rate due to the restricted heating capacity and fabrication capability in the manufacture of the insulation block.